"They could have prizes of £5,000, £10,000, £100,000 and higher," he said. "We have things that are called progressive jackpots, and progressive jackpots essentially allow for every coin that goes in - the prize increases by a small proportion."

Mr Tottenham said this had seen jackpots "in the order of four million dollars" (£2.5 million) - at Caesar's other casinos around the world.

His comments are likely to harden opposition to Labour's Gambling Bill, which receives it second reading in the Commons on Monday.

Charities, churches and welfare groups have warned the deregulation of the betting industry will result in an explosion of gambling addicts. The Salvation Army said research had shown fruit machines to be the most addictive form of gambling.

"These machines have never been available in the UK before and research from around the world shows they are some of the most addictive forms of gambling there are," said a spokesman.

He said: "It is too simplistic to actually say that just by putting machines in casinos, you will find there is an increase in problem gambling."

He also played down suggestions the deregulation of the casino industry would see the creation of hundreds of regional so-called super casinos. "This is about modernising legislation. It is about bringing Britain into step with the rest of the world," he said, adding: "It is not about ... suddenly Felixstowe becomes Las Vegas and so on. That is ridiculous."

A spokesman for the Department of Culture, Media and Sport confirmed there would be no limit on the size of the jackpots. He said it would be up to the operators to decide the size of the jackpot. "In theory there will be no upper limit," said the spokesman.